With organic soils wetting or lack of it can cause a lot of the problems, both alluvial clays and composts become hydrophobic (water repentant) once they pass a certain level of desiccation (drying out) What this means is despite your soil looking wet and feeling heavy the water is being suspended electrostatically between highly water repellent particles, the solution to this is to add a saponification agent to your water to reduce the surface tension, I know its a long way from organic but i simply put a small drip of washing up liquid on my finger and dip it into the water, to my mind it is such an insignificant amount of chemically derived soap its not worth worrying about any alternative but you could use any soap. This breaks the surface tension and allows the water to penetrate the clays and compost and only needs doing if you allow your soil to dry too much, if the soil is even moderately moist this is not an issue.
